DP gone out for the night with the 'lads', but due to drive at 9-10 tomorrow as planned to go see an old mate and get out of my hair whilst i do my dissertation.
He has form for wanting to drive the morning after a heavy session and sometimes he gets a bit angry/annoyed if i dare suggest the alcohol may still be in his system even though he feels fine.
I have a pack of the france breathalysers that you need to carry in your car when over there, and don't think he can argue with that!
My judgement may be clouded by annoyance as we had planned to spend the night together and he's also just text asking for a lift home at 3, which most certainly won't be happening 
I'm also not entirely sure he'll be going now, as he'll have a stinking hangover and he normally sleeps for the majority of the day after!
But wibu if i were to get him to do the breathalyser?